Library

feed icon rss

Your email was sent successfully. Check your inbox.

An error occurred while sending the email. Please try again.

Proceed reservation?

Export
  • 1
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 335 (1993), S. 351-358 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Ring Transformations of Heterocyclic Compounds. I. 2-Amino-benzophenones and 7-Oxo-hepta-2,4-dienenitriles by Reaction of 2,4,6-Triarylpyrylium Salts with 4-Nitrobenzyl Cyanide2,4,6-Triarylpyrylium salts 1 react with 4-nitrobenzyl cyanide in the presence of sodium acetate, triethylamine or triethylamine/acetic acid to give 7-oxo-hepta-2,4-dienenitriles 2. With stronger bases such as sodium methanolate or ethanolate a ring transformation of the salts 1 occurs giving rise to 2-amino-benzophenones 3 which can also be obtained by cyclization of the nitriles 2. Under the same conditions the 3-methyl-2,4,6-triphenylpyrylium salt 4 forms the 4-methyl-7-oxo-hepta-2,4-dienenitrile 5 by regioselective addition of the 4-nitrobenzyl cyanide at C-2 or it is converted to the 2-amino-5-methyl-benzophenone 6. The ring transformation of the pyrylium salts 1/4 by 4-nitrobenzyl cyanide represents a new and simple method for the preparation of 2-amino-benzophenones. - Spectroscopic data of the novel compounds are discussed; the structure of 5 was confirmed by a single crystal X-ray analysis.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 2
    Electronic Resource
    Electronic Resource
    New York, NY : Wiley-Blackwell
    Journal für Praktische Chemie/Chemiker-Zeitung 337 (1995), S. 46-49 
    ISSN: 0941-1216
    Keywords: Chemistry ; Organic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The hitherto unknown stereochemistry of N,N,N′,N′-tetrasubstituted 2-arylthioacrylamides 1 has been determined by X-ray crystal analysis and systematic NMR-investigations. Provided that the 2-aryl group lacks ortho substituents, compounds 1 exist predominantly as Z-isomers. In contrast, the major isomer has an E-s-trans configuration if the 2-aryl group is ortho-substituted. Substitution of the 3-amino group of 1 by glycinates, giving 3-aminothioacrylamides 2, generally preserves the original stereochemistry.
    Additional Material: 2 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
  • 3
    ISSN: 0044-2313
    Keywords: Diphenoxyphosphorylchloride ; N′,N′-dialkyl-N-diphenoxyphosphoryl urea ; N-diphenoxyphosphoryl-N″,N″-dipropyl biuret ; X-ray crystal structure analysis ; n.m.r. spectra ; Chemistry ; Inorganic Chemistry
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Description / Table of Contents: Reaction of Diphenoxyphosphorylchloride with N,N-disubstituted Ureas - Formation of Phosphorylated Biuret CompoundsN′,N′-disubstituted N-diphenoxyphosphorylureas, (PhO)2P(O)—NH—CO—NR1R2 (R1 = R2 = Et, 1; n-Pr, 2; n-Bu, 3; i-Bu, 4; R1 = Me and R2 = Ph, 5) as well as phosphorylated biuret compounds, (PhO)2P(O)—NH—CO—NH—CO—NR1R2 are obtained in the reaction of diphenoxyphosphorylchloride with N,N-disubstituted ureas and triethylamine. The biuret derivatives are formed via (PhO)2P(O)NCO. Their yield rises if the reaction is carried out without amine. The X-ray crystal structure analysis of (PhO)2P(O)—NH—CO—NH—CO—NPr2, 8, shows that dimers exist in the crystal with intermolecular as well as intramolecular hydrogen bonds. The framework formed by atoms P—N1—C1(O4)—N2—C2(O5)—N3(C3)C6 is planar. The existence of a rotation barrier along the bond C2-N3 was detected by NMR spectroscopy.
    Notes: Bei der Umsetzung von Diphenoxyphosphorylchlorid mit N,N-disubstituierten Harnstoffen in Gegenwart von Triethylamin treten neben N′,N′-disubstituierten N-Diphenoxyphosphorylharnstoffen, (PhO)2P(O)—NH—CO—NR1R2 (R1 = R2 = Et, 1; n-Pr, 2; n-Bu, 3; i-Bu, 4; R1 = Me u. R2 = Ph, 5), immer auch N″,N″-disubstituierte N-Diphenoxyphosphorylbiuret-Verbindungen, (PhO)2P(O)—NH—CO—NH—CO—NR1R2 auf. Sie entstehen über intermediär gebildetes (PhO)2P(O)NCO. Die Ausbeute an Biuretderivaten steigt, wenn ohne Aminzusatz gearbeitet wird. Die Röntgen-Kristallstrukturanalyse von (PhO)2P(O)—NH—CO—NH—CO—NPr2, 8, zeigt, daß im Kristall Dimere mit sowohl inter- als auch intramolekularen Wasserstoffbrücken vorliegen. Das Gerüst von 8 mit der Atomfolge P—N1—C1(O4)—N2—C2(O5)—N3(C3)C6 ist nahezu planar. NMR-Untersuchungen beweisen die Existenz einer Rotationsbarriere um die Bindung C2-N3.
    Additional Material: 1 Ill.
    Type of Medium: Electronic Resource
    Library Location Call Number Volume/Issue/Year Availability
    BibTip Others were also interested in ...
Close ⊗
This website uses cookies and the analysis tool Matomo. More information can be found here...